The present invention relates to a vehicle door latch device, and more particularly, to a vehicle door latch device with a double action mechanism.
Previously, a double action mechanism (hereafter DA mechanism) has been provided in a door latch device for the purpose of improving the performance of crime prevention of the door latch device. It can be said that the DA mechanism is an improved mechanism of a previously well-known one-motion door opening mechanism. The conventional one-motion mechanism is approximately simultaneously capable of restoring the latch device from a locked state to an unlocked state and opening the door, when an inside open handle of the door is operated in a case where the door latch device is in the locked state.
On the contrary, the DA mechanism merely restores the latch device from the locked state to the unlocked state without opening the door, when the opening operation of the inside open handle is performed in the locked state. The DA mechanism opens the door in accordance with the door-opening actuation of the inside open handle only when the latch device is in the unlocked state. Accordingly, in order to open the locked door having a latch device with a DA mechanism by the inside handle, both a first door-opening actuation of the inside handle for restoring the latch device to the unlocked state from the locked state and a second door-opening actuation of the inside handle for releasing the latch device are necessary. Thus, the DA mechanism requires the double action of the inside open handle when opening the door, so that it can improve the performance of crime prevention of the door latch device.
The German Patent DE 4313248 C2 discloses a door latch device with a DA mechanism. This door latch device comprises an open lever (4) connected to an outside open handle of a vehicle door and arranged to open the door when the outside open handle is operated, and a lock lever (6) displaceable between an unlocked position where it makes a door-opening operation of the open lever effective and a locked position where it makes the door-opening operation of the open lever ineffective.
The German Patent door latch device further comprises an inner lever (5) connected to an inside open handle of the door, a release lever (9) relevantly provided between the inner lever (5) and the open lever (4) for actuating the open lever (4) when rotated, and an elongated slide link or connective member (14) relevantly provided between the inner lever (5) and the release lever (9). The inner lever (5) is arranged to perform an unlocking movement from its initial position (FIGS. 2, 4) to its open position (FIGS. 3, 5) by a first door-opening actuation of the inside open handle at the time when the lock lever (6) is in the locked position, and is arranged to perform an opening movement from the initial position to the open position by a second door-opening actuation of the inside open handle at the time when the lock lever (6) is in the unlocked position. The slide link (14) is displaceable between a connective position where it mechanically connects the inner lever (5) to the release lever (9) and a non-connective position where it disconnects the release lever (9) from the inner lever (5).
The slide link (14) has one end operatively connected to the lock lever (6), and is held at the non-connective position when the lock lever (6) is in the locked position. The slide link (14) is urged toward the connective position from the non-connective position by the elasticity of a spring (18). In the locked state of FIG. 2, when the unlocking movement of the inner lever (5) is performed by the first door-opening actuation of the inside open handle, the slide link (14) moves up to be displaced to the connective position as shown in FIG. 3 by the engagement between a part (15) of the inner lever (5) and a part (16) of the slide link (14), and consequently, the lock lever (6) is shifted to the unlocked position, but the release lever (9) does not turn.
When the inside open handle is released after the first door-opening actuation, the inner lever (5) is restored to the initial position as shown in FIG. 4. At this moment, the slide link (14) is once moved down toward the non-connective position by the contact with a part (11) of the inner lever (5), and after that, it is restored again to the connective position by the elasticity of the spring (18). In the unlocked state of FIG. 4, when the inner lever (5) is turned in the door-opening direction by the second door-opening actuation of the inside handle, the release lever (9) turns to operate the open lever (4), and the door is opened.
The above German Patent device has a problem in that the unlocking movement of the inner lever (5) by the first door-opening actuation of the inside handle is transmitted to the lock lever (6) through the slide link (14). This structure causes the slide link (14) to move against the elasticity of the spring (18) when the inner lever (5) returns to the initial position after the first door-opening actuation. This movement of the slide link (14) prevents the smooth restoration of the inner lever (5) to the initial position, and consequently, the feeling of quality of the device is lowered.
Accordingly, it is an object of the present invention to provide a vehicle door latch device with a double action mechanism which overcomes the above-mentioned problem. In order to attain this object, the present invention employs a structure where the unlocking movement of the inner lever by the first door-opening actuation of the inside open handle is substantially transmitted to the lock lever in direct.